Confusing about CRM using "Messages" with the Organization service, can anybody explain why they use "Messages"?

I just started learning CRM development, when I read the documentation, one terminology "Messages" is confused me.

For example, below link:

https://docs.microsoft.com/en-us/powerapps/developer/common-data-service/org-service/use-messages

From my understanding, it should use "Events" instead of using "Messages", because actually, the "Messages" word used in Organization Service pipe line, it really is all Events triggered.  So I have to remember it in heart it meant events in here.

Can anybody have any insight why CRM uses "Messages" in this context?

Thanks